One critical challenge for engineers is to measure distances with ever greater accuracy. In recent years, this has become possible with nanometer resolution over distances of a few meters. That means to an accuracy equivalent to about the width of a human DNA strand. Although impressive, engineers would dearly love to have that kind of accuracy over much longer distances.
Now Yan-Wei Chen at the University of Science and Technology of China in Hefei, and colleagues, have found a way to do just that. They say they can measure distances greater than 100 kilometers with nanometer accuracy and that their breakthrough will have immediate applications in a wide range of frontier science and engineering projects.
For many years, the most accurate distance measurements have employed light-based technologies such as laser radar or lidar. This measures the time photons are in flight to determine the distance they travel. It is limited ...
